Pallet

ABSTRACT

A pallet constructed from formed sheet material, such as a plastic sheet, having a generally planar load-supporting member from which downwardly depend hollow leg members and hollow stiffening members, the leg and stiffening members being of such configuration and dimensions and so disposed that sufficient rigidity is imparted to said load-supporting member that the latter is relatively undeformable under normal loads thereon.

D United States Patent 1151 3,640,229

Bell 5] Feb. 8, 1972 [54] PALLET 3,433,184 3/1969 Addy ...108/533,467,032 9/1969 Rowlands et ...l08/5l [72] lg ggg 3,511,191 5/1970Barry, Jr. et al. ..108/58 [22] Filed: Oct. 6, 1969 PrimaryExaminer-Francis K. Zugel Assistant Examiner-Glenn O. Finch [211 Appl'863391 Attorney-Hill, Sherman, Meroni, Gross & Simpson [52] U.S.Cl..108/58 [57] ABSTRACT [51] lnt.Cl.

A pallet constructed from formed sheet material, such as a [58] Field ofSearch ..l08/5 1-58 plastic Sheet, having a generally planar 10a dsupporfing member from which downwardly depend hollow leg members [56]References (med and hollow stiffening members, the leg and stifieningmembers UNITED STATES PATENTS being of such configuration and dimensionsand so disposed that sufiicient rigidity is imparted to saidload-supporting Sullivan member that the latter is relatively undefomable under nor- 3,228,358 H1966 Sepe et al. 108/58 ma] loads thereon3,277,849 10/1966 Talbot ..108/58 3,359,929 12/1967 Carlson ..108/58 10Claims, 8 Drawing Figures PALLET BACKGROUND OF THE INVENTION Theinvention is directed to a pallet structure for so supporting an objector a load of material that the pallet and load may be readily picked upby a fork lift truck and transported as desired.

Pallets of this type normally are constructed of wood and may weigh asmuch as 30 pounds or more. At the same time, such pallets are relativelycostly as they must be manufactured by hand from wood stock, and arealso quite bulky as they cannot be nested but must be stacked one uponthe other. A further disadvantage of a wood pallet is the fact thatbeing composed of a number of wooden pieces, deterioration takes placewith age as well as a possible loosening up of the respective partscomprising the same whereby the pallet loses much of its originalrigidity.

The present invention therefore is directed to a pallet structure whicheliminates such disadvantages.

BRIEF SUMMARY OF THE INVENTION The present invention is directed to apallet structure which is designed for fabrication from one or morepieces of sheet material such as sheet plastic in which the formingoperation may take place, for example, by the utilization ofvacuumforrning techniques in which the plastic sheet or sheets areheated and then subjected to the action of a vacuum, whereby the sheetmaterial is drawn into the configuration of a mold or die to conform tothe configuration of the latter, forming a substantially planar loadsupporting member having hollow legs and stiffening ribs integrallyformed therewith as well as a reinforcing edge bead. The proportioningof the legs and stiffening ribs, as well as their locations anddirections are so selected that the load supporting member of the palletwill have sufficient rigidity to be relatively undeformable under thenormal loads which are to be carried by the pallet. This is achieved, inpart, by disposing the ribs and legs along intersecting lines wherebythe stifi'ening action of the legs and ribs is effected in transversedirections. The sidewalls of the leg and rib members preferably have atleast a slight degree of divergence upwardly whereby the pallets areself nesting and thereby require a comparatively small amount of storagespace.

Pallets constructed in accordance with the present invention may weighas little as three pounds or more than 12 pounds, depending upon theloads which must be supported and therefore the thickness of thematerials which must be employed. In addition to the advantages setforth above, the pallets are relatively indestructible, not beingeffected by the elements, substantially impervious to insects and thelike and being of one-piece construction eliminates separation and lossof parts of the pallet as well as a loosening up of the componentsthereof.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantagesof the invention will be readily apparent from the following descriptionof certain preferred embodiments thereof, taken in conjunction with theaccompanying drawings, wherein like reference characters indicate likeor corresponding parts, although variations and modifications may beeffected without departing from the spirit and scope of the novelconcepts of the disclosure, and in which:

FIG. 1 is a top plan view of a pallet embodying the present invention;

FIG. 2 is an end elevation of a pallet illustrated in FIG. 1

2 DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings andmore particularly to FIGS. 1 through 3, the reference numeral 1indicates generally a pallet constructed in accordance with the presentinvention which is formed from a generally rectangular sheet of plasticmaterial, as forexample a polyethylene, which has a generallyhorizontally extending load supporting member 2 which is providedadjacent its periphery with a reinforced edge indicated generally by thenumeral 3 of generally S-shaped transverse cross section. Extendingdownwardly from the load supporting member 2 are respective comer legs 4and intermediate legs 4', the respective legs being integrally fonnedfrom the material ofthe load supporting member 2. Also extendingdownwardly from the load supporting member 2 are a plurality ofstiffening ribs 5 and 6, the ribs 5 extending generally transversely asviewed in FIG. 1 while the ribs 6 extend generally vertically as viewedin FIG. 1. As will be apparent from a reference to FIG. 2, both the legs4, 4' and ribs 5, 6 are of hollow construction, being open at the topthereof and having sidewalls which diverge slightly in an upwarddirection, providing adequate draft during the vacuum-forming operationand at the same time providing a very rigid construction that willpermit nesting of a plurality of pallets.

In the embodiment illustrated in FIG. 1 each of the leg portions 4'and4' is provided with a plurality of outwardly extending generallyvertically directed ribs 7 which are generally sernicylindrical intransverse cross section and have upwardly diverging sidewalls toprovide the desired draft and facilitate nesting of the pallets. It willbe noted that the legs and stiffening ribs extend along intersectinglines whereby the stiffening action is effected in generally alternatingtransverse directions resulting in a load supporting structure that willhave relatively little deformation in a downward direction whensubjected to the normal loads to be carried thereby.

Also contributing to the overall rigidity of the load supporting surfaceis the specific configuration of the peripheral edges of the loadsupporting member, the details of which are illustrated in FIG. 3. Itwill be noted that the edge portion, indicated generally by the numeral3, comprises a generally inverted U-shaped portion indicated generallyby the numeral 8 which is connected adjacent its outer edge with aU-shaped portion 9, the latter terminating at its upper edge in ahorizontally extending portion 11, the outer edge of which terminates ina downwardly extending flange 12. In the embodiment illustrated,- theinverted U-shaped portion 8 has a flat top wall 13 and relatively flatdownwardly diverging sidewalls l4 and 15, the latter wall being extendedto form the adjacent sidewall of the U-shaped portion 9. Thisconstruction results in a relatively very stiff edge which stronglyresists downward flexing, with the inverted U-shaped portion 8 forming aperipheral lip at the edge of the load supporting portion 2 tending torestrict sliding movement of a load on the member 2 and thus insureretention of such load thereon.

Assuming the pallet illustrated in FIG. 1 is fabricated from a sheet ofpolyethylene having a thickness of 0.080 inches, the finished palletwill have an approximate weight of six pounds. At the same time such apallet will carry a load distributed over the load supporting member 2of approximately 2,000 to 3,000 pounds. Likewise, if the pallet is madefrom a sheet of polyethylene having a thickness of 0.125 inches thefinished pallet will have an approximate weight of 12 pounds and anapproximate load carrying capacity of over 3,000 pounds. Where alighterweight pallet is desired, for somewhat lesser loads, a laminated sheetstock may be employed, for example such as illustrated in FIG. 4, inwhich two sheets 16 of polyethylene, each of 0.030 inch in thickness,are laminated to a central core 17 of plastic foam, of for example,0.250 inch in thickness. A finished pallet fabricated from such stockwill have an approximate weight of 3 pounds and an approximate loadcarrying capacity of over 3,000 pounds.

Tests have indicated that for the majority of applications where solidstock is employed the plastic sheet material will normally run inthickness from 0.080 inch to a maximum of approximately 0.150 inch.Obviously, depending upon the application, where a laminated structureis employed, the thickness of the sheet stock will normally run between0.030 and 0.125 with the inner core normally being on the order ofapproximately 0.250. The total thickness of the stock forming the palletthus would normally run from approximately 0.080 to 0.500 inch inthickness. However, in special applications other specific thicknessesmay be employed.

FIGS. 5-8 illustrate additional arrangements of the supporting legs andstiffening ribs in accordance with the present invention, and againsize, number and arrangements of the supporting legs and stiffening ribswill depend to a certain extent on the sheet stock employed, the loadcarrying capacity of the pallet, etc. Where thinner sheet material isemployed, normally the span between stiffening ribs and between ribs andlegs will normally be less than where a heavier stock is employed.Consequently, arrangements such as illustrated in FIGS. 1 and 5 wouldnormally be employed in connection with pallets formed from lightermaterials while arrangements such as illustrated in FIGS. 6, 7 and 8would normally be employed with heavier stock.

It will also be appreciated that while the arrangements of FIGS. 5-8 donot illustrate the use of additional reinforcing ribs 7 on thesupporting legs, such ribs may be applied to any one of sucharrangements, the omission thereof being primarily for the purposes ofclarity.

It will be appreciated from the above disclosure that I have provided aone-piece, very lightweight pallet which possesses a relatively highdegree of rigidity even though it is made from comparatively thin sheetmaterial, and which may be readily nested with like pallets to afford aconsiderable savings in storage space.

I claim:

1. A pallet structure constructed of thin sheet material ofsubstantially uniform thickness throughout, and having a generallyplanar load supporting member, a plurality of downwardly directed hollowlegs formed from said sheet material and opening on the upper face ofsaid load supporting member, said legs being symmetrically disposed withone leg disposed adjacent each comer of the load supporting member andintermediate legs disposed therebetween, said legs being so arrangedthat the fork of a lift truck may be inserted therebetween, a pluralityof elongated downwardly directed hollow reinforcing ribs extendingbetween such legs and opening on the upper face of said load-supportingmember, the depth of said stiffening ribs being less than the depth ofsaid legs to permit such a fork lift to pass under such stifiening ribs,said legs having reinforcing ribs which extend laterally outward fromthe associated leg sidewall and upwardly with the upper ends thereofopening on said load-supporting surface, a continuous reinforcing edgestructure encircling said loadsupporting member and formed from saidsheet material, said edge structure comprising a first portion, ofinverted U-shape, in transverse cross section, having a pair of spacedsidewalls and a top wall connecting said sidewalls, the inner sidewallof said portion extending upwardly from said planar load-supportingmember to provide a peripheral abutment encircling the same, the outersidewall terminating at its lower edge in an outwardly directed bottomwall, the latter having at its outer edge an upwardly directed sidewallto form a second portion of U-shape in transverse cross section, withthe intermediate side wall forming a part of both U-shaped portions.

2. A pallet structure according to claim 1, wherein the respective top,bottom and sidewalls of said U-shaped portions are substantially flat.

3. A pallet structure according to claim 1, wherein the outer sidewallof the second U-shaped portion is provided with a longitudinallyextending reverse bend to form a longitudinally extending downwardlydirected flange defining the extreme outer edge of the pallet structure.

4. A pallet structure according to claim 1 wherein said legs andstiffening ribs are generally rectangular in horizontal cross sectionand generally U-shaped in transverse vertical cross section.

5. A pallet structure according to claim 1, wherein said legs andstiffening ribs are disposed on intersecting lines.

6. A pallet structure according to claim 1, wherein said U- shapedportion of said edge structure adjacent said load-supporting member hasa substantially flat top wall and relatively flat sidewalls whichdiverge from said top wall.

7. A pallet structure according to claim 1, wherein said pallet is madefrom sheet stock having an initial thickness of from approximately 0.030inch to approximately 0.150 inch and has a maximum thickness ofapproximately 0.080 to 0.500 inch.

8. A pallet structure according to claim 7, wherein said sheet stock isa polyethylene.

9. A pallet structure according to claim 7, wherein said pallet is madefrom single thickness of sheet stock having an approximate thickness offrom 0.080 to 0.150 inch.

10 A pallet structure according to claim 7, wherein said palletcomprises a laminated structure having two spaced outer plies of sheetplastic of at least 0.030 inch, between which is disposed a sheet offoam plastic having a thickness of approximately at least 0.250 inch.

1. A pallet structure constructed of thin sheet material ofsubstantially uniform thickness throughout, and having a generallyplanar load supporting member, a plurality of downwardly directed hollowlegs formed from said sheet material and opening on the upper face ofsaid load supporting member, said legs being symmetrically disposed withone leg disposed adjacent each corner of the load supporting member andintermediate legs disposed therebetween, said legs being so arrangedthat the fork of a lift truck may be inserted therebetween, a pluralityof elongated downwardly directed hollow reinforcing ribs extendingbetween such legs and opening on the upper face of said load-supportingmember, the depth of said stiffening ribs being less than the depth ofsaid legs to permit such a fork lift to pass under such stiffening ribs,said legs having reinforcing ribs which extend laterally outward fromthe asoicated leg sidewall and upwardly with the upper ends thereofopening on said load-supporting surface, a continuous reinforcing edgestructure encircling said load-supporting member and formed from saidsheet material, said edge structure comprising a first portion, ofinverted U-shape, in transverse cross section, having a pair of spacedsidewalls and a top wall connecting said sidewalls, the inner sidewallof said portion extending upwardly from said planar load-supportingmember to provide a peripheral abutment encircling the same, the outersidewall terminating at its lower edge in an outwardly directed bottomwall, the latter having at its outer edge an upwardly directed sidewallto form a second portion of U-shape in transverse cross section, withthe intermediate side wall forming a part of both U-shaped portions. 2.A pallet structure according to claim 1, wherein the respective top,bottom and sidewalls of said U-shaped portions are substantially flat.3. A pallet structure according to claim 1, wherein the outer sidewallof the second U-shaped portion is provided with a longitudinallyextending reverse bend to form a longitudinally extending downwardlydirected flange defining the extreme outer edge of the pallet structure.4. A pallet structure according to claim 1 wherein said legs andstiffening ribs are generally rectangular in horizontal cross sectionand generally U-shaped in transverse vertical cross section.
 5. A palletstructure according to claim 1, wherein said legs and stiffening ribsare disposed on intersecting lines.
 6. A pallet structure according toclaim 1, wherein said U-shaped portion of said edge structure adjacentsaid load-supporting member has a substantially flat top wall andrelatively flat sidewalls which diverge from said top wall.
 7. A palletstructure according to claim 1, wherein said pallet is made from sheetstock having an initial thickness of from approximately 0.030 inch toapproximately 0.150 inch and has a maximum thickness of approximately0.080 to 0.500 inch.
 8. A pallet structure according to claim 7, whereinsaid sheet stock is a polyethylene.
 9. A pallet structure according toclaim 7, wherein said pallet is made from single thickness of sheetstock having an approximate thickness of from 0.080 to 0.150 inch.
 10. Apallet structure according to claim 7, wherein said pallet comprises alaminated structure having two spaced outer plies of sheet plastic of atleast 0.030 inch, between which is disposed a sheet of foam plastichaving a thickness of approximately at least 0.250 inch.